Embodiments of the present disclosure relate generally to fluorescence imaging, and more particularly to systems and methods for suppression of background species during nerve imaging.
Surgical procedures, including laparoscopic studies and interventions, are prone to cause iatrogenic nerve damage, which in turn, may lead to loss of function, loss of sensation, muscle atrophy and/or chronic neuropathy in a patient. Often, such damage is caused inadvertently during surgery due to poor visibility of a target species, for example nerves, in comparison to surrounding tissues. Accordingly, certain imaging systems employ anatomical landmark identification for imaging the target species. Certain other systems use optical imaging for microscopic and/or macroscopic visualization of the target species. For example, in recent times, systems employing fluorescence image guided surgery have been used for visualizing nerves and other critical structures during surgery.
Particularly, fluorescence imaging allows highlighting of biological molecules and structures by providing greater contrast and visualization of these structures to a clinician during surgery and/or endoscopy. To that end, a fluorescence agent (fluorophore) may be administered to a patient for targeted labeling of diseased structures, such as cancerous tumor margins) and/or for labeling of critical anatomical structures such as nerves or the ureter for visualization during clinical examination and/or surgery. Although the fluorophores are designed to label a particular species, for example nerves or tumor margins, nonspecific or competitive binding of the fluorophores may result in poor signal-to-background ratio (SBR) and/or limited dynamic range. Accordingly, many bright fluorophores that specifically label biological targets and have favorable biological and chemical properties may be eliminated from the development pipeline due to inadequate SBR, thus resulting in a dearth of efficient fluorophores.
Certain imaging systems, thus, have sought to use more efficient algorithms and/or acquisition protocols for improved fluorescent imaging. One conventional imaging system operating in the near-infrared spectrum, for example, describes use of a normalized fluorescence method that corrects for attenuation heterogeneity across a tissue surface. Specifically, the normalized fluorescence method employs a ratio-based correction, which corrects for measurements at the emission (fluorescence) wavelength. Typically, the corrections are made by dividing the measurements with geometrically identical light attenuation measurements in tissue at the same or similar wavelengths such as at the excitation wavelength.
Although, such conventional approaches may allow generation of fluorescence images indicative of spatially varying absorption in the imaged tissue, such approaches still fail to provide significant improvement in suppressing unintentionally labeled background tissues, while allowing for reliable identification of target biological tissues during imaging.